A liquid crystal display device includes a liquid crystal panel as a display panel and the liquid crystal panel does not emit light. Therefore, the liquid crystal display device necessarily includes a lighting device and an example of such a lighting device is described in Patent Document 1. The lighting device described in Patent Document 1 includes a light guide plate, alight source unit including LEDs as alight source, and a casing in which the light guide plate and the light source unit are arranged. The light source unit is detachably mounted in the casing with a sliding mechanism that enables the light source unit to slide along an edge surface of the light guide plate. In assembling the lighting device, the light source unit is slid along the casing and inserted therein while keeping a clearance between the light guide plate and the LEDs with a spacer. Then, a pressure member that presses the light source unit toward the light guide plate is arranged between the light source unit and the casing to keep the clearance between the light guide plate and the LEDs appropriately.